/* This file is part of the Palabos library.
 *
 * The Palabos softare is developed since 2011 by FlowKit-Numeca Group Sarl
 * (Switzerland) and the University of Geneva (Switzerland), which jointly
 * own the IP rights for most of the code base. Since October 2019, the
 * Palabos project is maintained by the University of Geneva and accepts
 * source code contributions from the community.
 *
 * Contact:
 * Jonas Latt
 * Computer Science Department
 * University of Geneva
 * 7 Route de Drize
 * 1227 Carouge, Switzerland
 * jonas.latt@unige.ch
 *
 * The most recent release of Palabos can be downloaded at
 * <https://palabos.unige.ch/>
 *
 * The library Palabos is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * The library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/* Code 2.2 in the Palabos tutorial
 */

#include <iomanip>
#include <iostream>
#include <vector>

#include "palabos2D.h"
#include "palabos2D.hh"

using namespace plb;
using namespace std;

typedef double T;
#define DESCRIPTOR plb::descriptors::D2Q9Descriptor

/// Describe the geometry of the half-circular channel, used in tutorial 2.
template <typename T>
class BounceBackNodes : public DomainFunctional2D {
public:
    BounceBackNodes(plint N, plint radius) : cx(N / 2), cy(N / 2), innerR(radius), outerR(N / 2) { }
    /// Return true for all cells outside the channel, on which bounce-back
    ///  dynamics must be instantiated.
    virtual bool operator()(plint iX, plint iY) const
    {
        T rSqr = util::sqr(iX - cx) + util::sqr(iY - cy);
        return rSqr <= innerR * innerR || rSqr >= outerR * outerR;
    }
    virtual BounceBackNodes<T> *clone() const
    {
        return new BounceBackNodes<T>(*this);
    }

private:
    plint cx;      //< X-position of the center of the half-circle.
    plint cy;      //< Y-position of the center of the half-circle.
    plint innerR;  //< Outer radius of the half-circle.
    plint outerR;  //< Inner radius of the half-circle.
};

void halfCircleSetup(
    MultiBlockLattice2D<T, DESCRIPTOR> &lattice, plint N, plint radius,
    OnLatticeBoundaryCondition2D<T, DESCRIPTOR> &boundaryCondition)
{
    // The channel is pressure-driven, with a difference deltaRho
    //   between inlet and outlet.
    T deltaRho = 1.e-2;
    T rhoIn = 1. + deltaRho / 2.;
    T rhoOut = 1. - deltaRho / 2.;

    Box2D inlet(0, N / 2, N / 2, N / 2);
    Box2D outlet(N / 2 + 1, N, N / 2, N / 2);

    boundaryCondition.addPressureBoundary1P(inlet, lattice);
    boundaryCondition.addPressureBoundary1P(outlet, lattice);

    // Specify the inlet and outlet density.
    setBoundaryDensity(lattice, inlet, rhoIn);
    setBoundaryDensity(lattice, outlet, rhoOut);

    // Create the initial condition.
    Array<T, 2> zeroVelocity((T)0., (T)0.);
    T constantDensity = (T)1;
    initializeAtEquilibrium(lattice, lattice.getBoundingBox(), constantDensity, zeroVelocity);

    defineDynamics(
        lattice, lattice.getBoundingBox(), new BounceBackNodes<T>(N, radius),
        new BounceBack<T, DESCRIPTOR>);

    lattice.initialize();
}

void writeGifs(MultiBlockLattice2D<T, DESCRIPTOR> &lattice, plint iter)
{
    const plint imSize = 600;
    ImageWriter<T> imageWriter("leeloo");
    imageWriter.writeScaledGif(
        createFileName("u", iter, 6), *computeVelocityNorm(lattice), imSize, imSize);
}

int main(int argc, char *argv[])
{
    plbInit(&argc, &argv);

    global::directories().setOutputDir("./tmp/");

    // Parameters of the simulation
    plint N = 400;  // Use a 400x200 domain.
    plint maxT = 20001;
    plint imageIter = 1000;
    T omega = 1.;
    plint radius = N / 3;  // Inner radius of the half-circle.

    // Parameters for the creation of the multi-block.

    // d is the width of the block which is exempted from the full domain.
    plint d = (plint)(2. * std::sqrt((T)util::sqr(radius) - (T)util::sqr(N / 4.)));
    plint x0 = (N - d) / 2 + 1;  // Begin of the exempted block.
    plint x1 = (N + d) / 2 - 1;  // End of the exempted block.

    // Create a block distribution with the three added blocks.
    plint envelopeWidth = 1;
    SparseBlockStructure2D sparseBlock(N + 1, N / 2 + 1);
    sparseBlock.addBlock(Box2D(0, x0, 0, N / 2), sparseBlock.nextIncrementalId());
    sparseBlock.addBlock(Box2D(x0 + 1, x1 - 1, 0, N / 4 + 1), sparseBlock.nextIncrementalId());
    sparseBlock.addBlock(Box2D(x1, N, 0, N / 2), sparseBlock.nextIncrementalId());

    // Instantiate the multi-block, based on the created block distribution and
    // on default parameters.
    MultiBlockLattice2D<T, DESCRIPTOR> lattice(
        MultiBlockManagement2D(
            sparseBlock, defaultMultiBlockPolicy2D().getThreadAttribution(), envelopeWidth),
        defaultMultiBlockPolicy2D().getBlockCommunicator(),
        defaultMultiBlockPolicy2D().getCombinedStatistics(),
        defaultMultiBlockPolicy2D().getMultiCellAccess<T, DESCRIPTOR>(),
        new BGKdynamics<T, DESCRIPTOR>(omega));

    pcout << getMultiBlockInfo(lattice) << std::endl;

    OnLatticeBoundaryCondition2D<T, DESCRIPTOR> *boundaryCondition =
        createLocalBoundaryCondition2D<T, DESCRIPTOR>();

    halfCircleSetup(lattice, N, radius, *boundaryCondition);

    // Main loop over time iterations.
    for (plint iT = 0; iT < maxT; ++iT) {
        if (iT % imageIter == 0) {
            pcout << "Saving Gif at time step " << iT << endl;
            writeGifs(lattice, iT);
        }
        lattice.collideAndStream();
    }

    delete boundaryCondition;
}
